Codex vs Claude Code: which coding agent should you use?

What is the difference between Codex and Claude Code?

Both products do the same basic job. You describe a task, the agent reads your repository, edits files, runs commands such as your tests, and shows you the result for review. The differences are in who makes them, which models they run, where they run, what they cost and how they handle safety and extension. This page uses facts from each vendor's own documentation and pricing pages, read on October 30, 2026. It deliberately leaves out benchmark scores and speed claims. Each vendor tests on its own setup, models change within weeks, and a number copied from a blog post is out of date by the time you read it.

How do Claude Code and Codex compare in detail?

The two entries below give each tool's facts. The order is alphabetical by vendor and is not a ranking.

Which one has the features you need?

The tables show a lot of overlap, which is the main finding. The big gaps are the model family, the open-source CLI and how each sells its plans. Beyond that the two have converged: both run in terminals and editors, both support the same extension ideas, and both read the shared AGENTS.md file. Anything that looks like a missing feature on one side may exist under a different name, so check the docs before you rule a tool out.

How do the prices and limits compare?

The entry points match: USD 20 a month for Claude Pro or ChatGPT Plus, as of October 2026, before tax. Anthropic discounts Pro to USD 17 a month if you pay USD 200 up front for the year. At the top, both vendors have a USD 100 tier, and both have tiers above it.

Neither vendor sells unlimited use. Anthropic limits usage every five hours and each week, and says how quickly you reach a limit depends on the model, chat length and file size. OpenAI says Codex usage depends on the model, the size and complexity of the task, and whether you run locally or in the cloud, and that tasks that look alike can consume different amounts. It also states that Pro plans currently have no five-hour limit. Because both are metered by what you ask, the cheapest tool is the one that finishes your kind of task in fewer attempts, and only your own test shows that.

For Anthropic's pay-as-you-go benchmark, its cost documentation reports an enterprise average of around USD 13 per developer per active day. OpenAI's pricing page instead gives estimated local messages per five-hour period for each model on Plus and Business plans, so the two vendors' figures are not directly comparable.

Which should you pick for your situation?

If none of these rows decides it, the tie-breaker is how each tool feels to you across one real task. Anthropic's own best-practices page and OpenAI's CLI page both advise the same working habits: give the agent something to check its work against, and keep a way to revert. That advice is the same in either tool, so you lose little by trying both.

Can you use both on the same project?

Yes, and the shared file makes it easy. Both read AGENTS.md. Codex reads it natively. Claude Code reads it when there is no CLAUDE.md, or you can create a CLAUDE.md that starts with @AGENTS.md and add Claude-only lines below it. One set of build commands and rules then serves both agents. Keep tool-specific settings (Claude hooks, Codex config.toml) in their own files.

Running both on the same branch at the same time invites conflicts, so give each its own git branch or worktree, and merge after you read both diffs. That is also the cleanest way to compare them.

How do you test Codex against Claude Code fairly?

Give both the same brief on the same starting commit, on separate branches, and score the results with the same checks. Pick a task with an objective finish line, such as tests that pass. If you have no project, take an idea from the developer tools category on the board, where every idea has a generated build prompt, and use that as the brief.

Task: [one sentence describing the feature or fix]

Context:
- Read AGENTS.md first.
- The test command is: [command]

Do this:
1. Propose a short plan and wait for my approval.
2. Implement it on this branch only.
3. Run the tests and fix failures.
4. Stop when the tests pass and tell me which files you changed and why.

Do not: add dependencies, change unrelated files, or edit migrations.

1. Create two branches from the same commit and run one agent on each.
2. Use the same approval level for both, such as asking before shell commands.
3. Record time to passing tests, number of corrections you made, and plan usage afterward.
4. Read both diffs. The one you could explain and maintain is usually the better result, even if it was slower.
5. Repeat on a second, different task before you decide. One task is an anecdote.